Every pork production system faces the challenge of what to do when it’s clear that young pigs won’t recover from disease, weakness or trauma and need to be euthanized in a timely, humane and safe manner.
This can be especially problematic with suckling pigs. Current approved methods including blunt force trauma and non-penetrating captive bolt are heavily criticized by consumers and animal rights organizations. And these methods may impact the caregivers’ well-being and psychology.
In contrast, electrocution induces a loss of consciousness in a rapid, timely manner and requires little training, based on Canadian research presented at the 2009 annual meeting of the American Association of Swine Veterinarians. When properly administered, electrocution will render the brain insensible and initiate cardiac fibrillation and death.
Traditionally, electrocution has not been used on young pigs under 10 lb. because the resistance of the skin surface can be less than the resistance through the body, causing the electrical current to flow on the surface of the skin rather than through the body.
Preliminary trials of the electrode design of Welbourne Innovations appear to have overcome this disadvantage for pigs greater than 3 days of age. This device is also equipped with user safety features that limit the chance of electrical exposure to the user.
The research trial attempted to validate that this novel electrocution device provides a safe, humane alternative to current euthanasia methods available for pigs from birth to 15 lb.
The first step with euthanasia via electrocution is validating a rapid loss of consciousness. Initially, a minimal time to loss of consciousness was established for two different times of electrocution in three different age and weight groups: pigs less than 3 days of age and less than 5 lb.; pigs greater than 3 days of age and less than 5 lb.; and pigs greater than 3 days of age and greater than 5 lb.
Thirty commercial pigs ranging from birth to 15 lb. were identified as ill, unthrifty or fallouts and requiring euthanasia. These animals were lightly anesthetized prior to electrocution. They were then placed in the electrocution device and a 110-120-volt current was applied for three or five seconds in Phase 1 of the study.
Cardiac and brain electrical activity were monitored using an electrocardiogram and an electroencephalogram, respectively. All electrocutions were videotaped and motor activities, such as kicks, paddling, gasps or vocalizations, were recorded.
The pigs were also evaluated for dilation of pupils, absence of corneal reflexes and absence of nociceptive (reacting to pain) reflexes to determine if level of unconsciousness correlated to a surgical loss of consciousness. If attained, that piglet was allowed to remain in the study.
Overall, the electrocution device was successful in inducing a loss of consciousness in all pigs at three- and five-second durations for the groups greater than 3 days of age and less than 5 lb. and greater than 3 days of age and greater than 5 lb. However, the group less than 3 days of age and less than 5 lb. was eliminated from the trial due to a poor stunning success rate of 70% at the five-second electrocution interval.
Pigs that failed to lose consciousness by electrocution were immediately and humanely euthanized via pentobarbital injection. If a pig started to regain consciousness after loss of consciousness, it was also euthanized.
In Phase 2 of the study, 66 sick pigs that needed to be euthanized (greater than 3 days of age and less than 5 lb., and greater than 3 days of age and greater than 5 lb.) were sedated and euthanized via electrocution at time intervals of 5, 10 and 15 seconds. The same monitoring equipment and data collection parameters were used as in Phase 1.
Deaths were achieved in 98.5% of pigs. The one unsuccessful euthanasia occurred in the greater than 3 days of age and less than 5 lb. group at 15 seconds. This pig was immediately euthanized via injectable pentobarbital.
One consideration for any euthanasia is the emotional and physical well-being of the caregiver doing the task. The device tested is designed with a door that will block the caregiver’s view of the pig during the electrocution and is also a safety feature. The most common involuntary reflex observed was occasional pig gasps (53%) or singular kicks (9.1%) after unconsciousness and during and/or after death.
This study suggests that electrocution using this novel device is a humane form of euthanasia when carried out in piglets greater than 3 days of age. Electrocution reliably induced unconsciousness at less than or equal to 3 seconds after the application of current. Electrocution also repeatedly induced death in piglets greater than 3 days of age at time periods equal to or greater than 5 seconds of current application time.
This research project was funded by the Pork Checkoff.
Researchers: Sarah Probst Miller, DVM, AgCreate Solutions, Inc.; Aaron Lower, DVM, Carthage (IL) Veterinary Service; Sherrie Clark, DVM, University of Illinois; Steve Welbourne, Welbourne Innovations; and Jessica McKinney, University of Illinois. For more information, contact Miller by phone at (217) 817-5016 or e-mail [email protected] To purchase the device, contact Steve Welbourne at Welbourne Innovations at [email protected]